vgrafx

that's weird.

in one post he said his wheels were +30, and in another his was +37.

and one post says he has 20mm spacer, and another was 1 inch spacer?

I'm confused.

anyway, for as flush as possible without rubbing, what size spacers do you think I need for front and rear if i'm at +35 front and +40 rear?

(on Michelin pilot sport 4S, 235/40/18 for front and 265/35/18 rear)

ScytheDC

I’m keeping an eye on this thread because I’m also into the aggressive fitment look. I had that fitment on my M3 and I can’t let it go.

OP, there’s a website that is able to calculate the expected overall size of your new wheel and tire setup and compare it to your original set up. I find this website to be the most helpful and very accurate. It will show you the distance from suspension components, and the effects of offsets, wheel sizes and tire sizes. I’ll see if I can find it and post it here. One measurement you need is the the distance from the fender to the outward face of your tire. Mess around with different sizes until you find a set up that gets you as close as possible to that fender. Then, the wheel gap needs to be closed with some lowering springs.

ScytheDC

Willtheyfit . com
I used that when getting wheels and tires for my M3. Got very close to what I wanted using this site.

vgrafx

It turns out that the wheel size I got was 18x9, not 18x8.5.

In that case, would 235/40/18 still work?

Sasnuke

You could use 235/40, 255/35, or 265/35...depends on the offset and if you prefer a taller or wider tire.

vgrafx

ok if the rear will be 265/35/18 for 9.5, i'll just go for 255/35/18 for the front at 9. i'm not sure how to really figure out exactly what i want. as long as it fits maybe the difference between 235/40 and 255/35 is small enough that it doesn't matter in the end.

Sasnuke

I didn't realize you were still going with a staggered setup.
In that case 235/40 front and 265/35 rear.

vgrafx

Oh, I don't think I understand the reasoning for this then. Are you saying if someone has a staggered set up, then they should have a narrower tire in the front?

235/40 is narrower than 255/35, right? but the sidewall will be taller?

I just figured if initially the wheel width was 8.5 and 235/40 was recommended, then if the wheel width changed to 9, then it would make sense to go with the wider 255/35.

And I'm not sure if this matters but I am no longer getting BC Coilovers because it would take too long. So for now, I have the RSR Downs for AWD coming and my plan is most likely only putting them in front.

The tires will most likely still be Michelin Pilot Sport 4S.

Sasnuke

The reason I recommend 235/40 for the front is to match the diameter of the rear.
Since the rear will be 265/35 the matching front will be 235/40.
If you put a 255/35 on the front, then the rear tire will literally be one size bigger...and on an AWD. The AWD may take exception to that.

In reality you could use 255/35 on all 4 rims, although there would be a little stretch on the rear.

vgrafx

Oh that makes sense then! Thank you, I know nothing about wheels and tires.

I'll stick with the 235/40 and 265/35.

ScytheDC

Take a quick look online about what the numbers in a tire size and a wheel size mean. Pair that info up with the specs of your future and current wheels, some measurements you take from your own car, and one of the wheel guide websites posted in this thread and you should easily be able to figure this out on your own easy.